prerequisites 1.0.5

Prerequisite functions to help and assert inputs and outputs condition and type

prerequisites

Small runtime validation helpers for preconditions and type checks.

Install

pip install prerequisites

What it provides

• Value checks: require, require_one_in_all, require_all_in_all
• Type checks: require_type, require_one_of_types, require_all_of_type, require_all_same_type, require_type_or_none
• Decorator checks: @validate_types for argument validation using type hints

Quick examples

Value checks

from prerequisites import require, require_all_in_all, require_one_in_all

require(2 > 1)
require_one_in_all([False, True, False])
require_all_in_all([True, 2 + 2 == 4])

Type checks

from prerequisites import (
    require_all_of_type,
    require_all_same_type,
    require_one_of_types,
    require_type,
    require_type_or_none,
)

require_type(10, int)
require_one_of_types(3.14, (int, float))
require_all_of_type([1, 2, 3], int)
require_all_same_type(["a", "b", "c"], (str,))
require_type_or_none(None, str)

Decorator validation

from prerequisites import validate_types

@validate_types
def add(a: int, b: int) -> int:
    return a + b

add(1, 2)      # ok
add("1", 2)   # raises TypeError

Shallow container behavior

@validate_types validates only outer container types for parameterized hints.

from prerequisites import validate_types

@validate_types
def count(values: list[int]) -> int:
    return len(values)

count([1, 2, 3])
count([1, "x"])  # valid in current shallow mode (still a list)

Notes

• @validate_types validates function arguments only.
• Return annotations are not enforced.
• Errors raise TypeError or ValueError depending on the helper.